Sound: They expanded the soundstage a noticeable amount as well as instrument separation between the 2 channels. However, at first listen on the standard music app, i found the vocals to be a little muddy or low end heavy. Not enough treble to bring out the details of the instruments or the singer's voice. So I tried using it in conjunction with the EQu app and to my surprise i found it worked alot better. I increased the treble to bring out the details better but with that brought less bass than i really wanted. So I put the amp on bass boost 2 and high gain and now they have a pretty solid impact in the bass without losing the detail of the treble. Now the only thing that would make this amp sound perfect is if it could bring the mids/vocals a tiny more forward in the sound spectrum. I could adjust the mids in EQu, but the result made them sound not as clear- it went back to the result of just having the amp playing through the standard music app.   7.5-8/10
 
 
Build: Decent. Since I got it used it was a little dented but hardly noticeable. the cover to the inside of the amp was backward when i got it, so i had to switch it back and even then one of the corners stuck out slightly. So even with the plastic exterior showing some wear and tear, i am confident the E11 won't up and break on me too easily.     7/10
 
 
Overall: These are my 24 hour initial impressions. So I can't say this is my definitive conclusion as only time will tell. But for now, I'm giving it a solid 7.5/10